Air sampling system

ABSTRACT

An atmosphere sampling system includes:
         an unmanned rotary-wing aircraft platform including: an airframe capable of lifting a selected payload mass; at least one motorized rotor; and, a flight control system including an on-board controller;   an atmosphere sampling unit having a total mass no greater than the selected payload mass, and including: a blower preferably having backward-facing blades, an inlet structure to draw in air to be sampled, and an outlet to discharge air after sampling; a plurality of sample containers; and, an indexing mechanism to move selected sample containers, one at a time, into contact with the inlet structure so that samples may be collected; and,   a power supply with sufficient capacity to operate the motorized rotor(s), the onboard portion of the flight controller, the blower, and the indexing system.

CROSS REFERENCE TO RELATED APPLICATION

This application is a Continuation of U.S. patent application Ser. No. 15/530,844, entitled “Air Sampling System” and filed by the present inventor on Mar. 17, 2017, now U.S. Pat. No. 10,330,571, the entire disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The invention pertains to apparatus and methods for collecting air samples, and more particularly to apparatus and methods for collecting air samples at known locations using a small unmanned aircraft.

Description of Related Art

There is an ongoing need for air sampling systems that are capable of being deployed remotely to sample stack emissions, plumes from gas or chemical leaks, dust or particulate plumes from stacks and dry conveyors, etc. More recently, interest has emerged in collecting a very specific type of particulate, viz., pathogenic cells, mold and mold spores, contaminated mists near air conditioning units and cooling towers, etc.

To consider one example, a recent report (Reuters News, September 2016) stated, “Corn mold lurks in U.S. fields, threatening crop yield.” According to some estimates, mold may be responsible for destroying one-third of arable crops. This is more than a nuisance; it represents a serious economic loss to the farmer and to society in general.

The economic damage could be reduced by geolocating mold and providing these data to farmers. This would help farmers increase their yield by accurately locating mold in crop fields for effective mold remediation. Mold location data would allow farmers to reduce the risk associated with mold by implementing proactive risk management that allows farmers to treat the mold before damages occur. Ideally, a system should collect samples that can be identified later in the lab to provide the exact species of mold and recommend an optimal treatment strategy. An optimal strategy would use the mold location data to allow the farmer to treat only the infected area of the field, reducing the amount of fungicides used.

Small Unmanned Aircraft Systems (sUAS) operated under FAA's Part 107 have begun to be used to collect samples of various kinds. In one approach, a multi-rotor drone carries an inflatable sample bag that can be filled with an air sample for later analysis [Scentroid DR1000 Flying Laboratory, 431 Alden Rd. #3, Markham, Ontario, Canada]. It will be appreciated, however, that collecting particulates, especially biological samples, is more difficult than simply inflating a small, collapsible bag. Typically, a significant volume of air must be drawn through a porous capture medium, which might be a sheet of filter paper or a wad of fibrous material, so that the total number of spores or cells contained in that volume of air may be concentrated into a small sample for examination, analysis, or culture. Such filter-based air samplers typically employ positive-displacement (piston-type) pumps, which are inherently very heavy machines and generally unsuitable for deployment on low-cost rotary-wing sUAS, which typically have very limited payload capacity.

OBJECTS AND ADVANTAGES

Objects of the present invention include the following: providing a robust, user-friendly system for remote air sampling; providing a particulate sample collection system that is light enough to be deployed on a small unmanned aircraft system; providing a system for geolocating mold or other pathogens; providing a system to collect and archive multiple samples of pathogenic particulates at preselected locations for later analysis; and providing an airborne sample collection system that may be operated in real time from the ground or operated to autonomously follow a preprogrammed flight plan. These and other objects and advantages of the invention will become apparent from consideration of the following specification, read in conjunction with the drawings.

SUMMARY OF THE INVENTION

According to one aspect of the invention, an atmosphere sampling system comprises:

-   -   an unmanned rotary-wing aircraft platform comprising:         -   an airframe capable of lifting a selected payload mass;         -   at least one motorized rotor; and,         -   a flight control system including an on-board controller;     -   an atmosphere sampling unit having a total mass no greater than         said selected payload mass, and comprising:         -   a blower having backward-facing blades, an inlet structure             to draw in said atmosphere to be sampled, and an outlet to             discharge said atmosphere after sampling;         -   a plurality of sample containers, each having a porous             sample collecting medium therein; and,         -   an indexing mechanism to move selected sample containers,             one at a time, into contact with said inlet structure so             that samples may be collected on said porous medium; and,     -   a power supply with sufficient capacity to operate said         motorized rotor(s), the onboard portion of said flight         controller, said blower, and said indexing system.

According to another aspect of the invention, an atmosphere sampling system comprises:

-   -   an unmanned rotary-wing aircraft platform comprising:         -   an airframe capable of lifting a selected payload mass;         -   at least one motorized rotor; and,         -   a flight control system including an on-board controller;     -   an atmosphere sampling unit having a total mass no greater than         said selected payload mass, and comprising:         -   a blower having backward-facing blades, an inlet structure             to draw in said atmosphere to be sampled, and an outlet to             discharge said atmosphere after sampling;         -   at least one sample analyzer upstream of said inlet             structure and including a sensor for measuring at least one             characteristic of said atmosphere as it flows through said             analyzer; and,     -   a power supply with sufficient capacity to operate the motorized         rotor(s), the onboard portion of the flight controller, the         blower, and the sample analyzer.

According to another aspect of the invention, a method for atmospheric sampling comprises the steps of:

-   -   mounting an atmospheric sampling device to a small unmanned         aircraft system (sUAS) that is capable of moving from one         location to another and hovering at selected locations for         selected times;     -   directing said sUAS to one or more selected location(s);     -   keeping said sUAS at each of said selected location(s) for a         sufficient time to allow a sample to be collected;     -   obtaining geolocation data corresponding to each of said         location(s) so that each sample may be associated with the         location in which it was collected.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings accompanying and forming part of this specification are included to depict certain aspects of the invention. A clearer conception of the invention, and of the components and operation of systems provided with the invention, will become more readily apparent by referring to the exemplary, and therefore non-limiting features illustrated in the drawing figures, wherein like numerals (if they occur in more than one view) designate the same elements. The features in the drawings are not necessarily drawn to scale.

FIG. 1 is a schematic diagram of one example of the present invention showing the preferred components of a functional system.

FIG. 2 is a schematic diagram of a sampling system in accordance with another aspect of the invention.

FIG. 3 is a schematic diagram of the same sampling system, viewed in an orthogonal direction relative to the previous view.

FIG. 4 is a schematic diagram of a linear magazine containing sampling cartridges.

FIG. 5 is a schematic diagram of a drum-type magazine for handling a plurality of sampling cartridges.

FIG. 6 is a schematic diagram in cross section of a drum-type magazine showing one arrangement of cartridges therein.

FIG. 7 is a schematic diagram of a blower casing configuration and the resulting airflow in accordance with one aspect of the invention.

FIG. 8 is a schematic diagram of the internal configuration of the blower in the previous figure.

FIG. 9 is a schematic diagram of a blower having a backward-facing blade (arrow indicates the direction of rotation).

FIG. 10 is a schematic diagram of a blower having a forward-facing blade.

FIG. 11 is a schematic diagram of a blower having radial blades.

FIG. 12 is a schematic diagram of a blower in side view.

FIG. 13 is a schematic diagram of the blower in the previous figure with its associated casing.

FIG. 14 is a schematic diagram of a blower having a single shaft on the rear side.

FIG. 15 is a schematic diagram of the blower in the previous figure with its associated casing.

FIG. 16 is a schematic diagram of a blower with a drive shaft accessible from either side.

FIG. 17 is a schematic diagram of the blower in the previous figure with its associated casing.

FIG. 18 is a schematic diagram of the steps in a sampling mission in accordance with one aspect of the invention.

FIG. 19 is a flow chart showing the sequence by which air passes through the system in accordance with one aspect of the invention.

DETAILED DESCRIPTION OF THE INVENTION

In its most general sense, the invention comprises a small unmanned aircraft platform carrying an air sampling system, including multiple sampling cartridges, or a single testing chamber, that can fly from one selected sampling location to another, either autonomously or under remote control, and return the sample cartridges for later analysis or collect data in flight for later analysis. Various aspects of the invention will be described in more detail in the exemplary materials that follow.

Example

-   -   Unmanned Aircraft System     -   One suitable sUAS-based delivery system, illustrated         schematically in FIG. 1, is a custom built octocopter that is         operated under FAA's Part 107 as a sUAS (Small Unmanned Aircraft         System). The octocopter consists of the following components:         one airframe 3 [Tarot Model T18 Frame, No. 1, Puzhou Phase III         Industrial Zone, Lucheng District Wenzhou City, Zhejiang         Province, China], eight brushless motors 2 [Tarot Model 5008],         eight carbon fiber propellers 1 (two are shown) [Tarot Model         1855], eight electronic speed controllers (part of flight         controller module 5 for the controller aspect, but also part of         6 because it supplies power to the motors)) [FlyFun 60A,         Hobbywing, Building 4, Yasen Chuangxin Hi-tech Industrial Park,         8 Chengxin Road, Baolong Industrial Town, Shenzhen, China],         power supply 6 containing two batteries [Graphene 16000 mAh 22.2         v, Turnigy, Block B, 2 Floor, Merit Industrial Center, 94         Tokwawan Road, Tokwawan, Kowloon, Hong Kong], flight controller         5 [Pixhawk, 3DR, 1608 4th Street, Suite 410, Berkeley, Calif.],         two voltage regulators with 3 amps at 5.30 volts output, [Mauch         Electronics, 177 Mei Ai Lu, Baoshan Qu, Shanghai Shi, China],         handheld radio transmitter 15 [Taranis X9D, FrSky, F-4, Building         C, Zhongxiu Technology Park, No. 3 Yuanxi Road, Wuxi, 214125,         Jiangsu, China], radio receiver (part of communication module 4)         [X8R, FrySky], two receivers [NEO-M8N Triple Band receiver with         EMI protection and HMC5983 Compass PRO version, CSG Shop,         http://www.csgshop.com/], and radio modem (would be part of         communication module 4 and handheld radio treansmitter 15)         [RFDesign Model 900+, Unit 7/1 Stockwell Place, Archerfield,         Queensland, Australia].     -   The software that controls the octocopter from the 3DR Pixhawk         flight controller is Ardupilot. Mission Planner, a free and open         source software ground station application, was downloaded onto         a computer. The ArduCopter, a specific version of ArduPilot,         firmware was then installed onto the 3DR Pixhawk through the         Mission Planner software. The complete instructions on         installing ArduCopter using Mission Planner can be found at         http://ardupilot.org/plannerfindex.html. It should also be noted         that ArduCopter could be installed with similar ground station         applications: APM Planner 2, MAVProxy, QGroundControl, and         Universal Ground Control Station.

The invention may further include a “companion computer”, which is a device that travels on board the sUAS and allows developers to create powerful applications, using onboard computing, that communicates with the flight controller. Companion computers typically run computation intensive programs or time-sensitive tasks such as intelligent path planning, computer vision, and 3D modeling. Companion computers can also add the benefit of running additional sensors or actuators that cannot be controlled through the flight controller. An alternative approach would be to process the information at the ground control station or cloud then resend the computed information back to the drone while stationary or inflight. The user can select the most appropriate computational approach depending on routine engineering considerations such as mission time, complexity, on-board computing capacity, and data processing requirements.

As used herein, the term “flight controller” is intended broadly to include any of the following: on-board data processors, companion computers, and cloud or ground control computer processing, as the geolocation data could be recorded in any of these locations.

Example

-   -   The sUAS described above has a flight time of roughly 32 minutes         (20% of battery remaining) when hovering out of ground effect         with zero payload. The sUAS has a mass of roughly 9 kg and can         carry a maximum payload of 12.7 kg. The flight endurance at         gross weight was not determined.

Example

-   -   Air sampler     -   An air sampler, FIGS. 2 and 3, was designed to be suspended         below the sUAS-based delivery system via supports 7 and base         plate 13 on rails that are integrated into the Tarot T18 Frame.         The sampler consists of a sampling cartridge 10, a 9-sample         rotary cartridge holder 14, driven by servo 12 [S125 Digital         Servo, GWS, 1F., No. 125, SEC. 2, Datung Road., Shijr City,         Taipei 221, Taiwan], a 12-volt centrifugal blower 11 [Quick-Fill         080, Intex, 1665 Hughes Way, Long Beach, Calif.], voltage         regulator 31 with 5 amps at 5 volts and 10 amps at 12 volts         outputs (may be part of 31 or incorporated into the blower         module 11), [Multistar, Tumigy, Block B, 2 Floor, Merit         Industrial Center, 94 Tokwawan Road, Tokwawan, Kowloon, Hong         Kong], and a receiver-controlled switch [Tumigy, Kowloon, Hong         Kong].     -   Each sampling cartridge 10 attaches to the rotary cartridge         sampler (revolver) 14 which can hold a total of 9 cartridges.         The cartridge is then indexed into position proximate to blower         intake pipe 8 and connecting pipe 9 using the GWS S125 Digital         Servo 12 below the centrifugal blower by receiving a signal from         the 3DR Pixhawk flight controller 5. Once the sample has been         indexed, the Tumigy receiver-controlled switch turns on the         centrifugal blower 11 once it receives the signal from the 3DR         Pixhawk to begin taking a sample. The exhaust air from the         centrifugal blower then cools the Tumigy Multistar Voltage         Regulator 31 with 5 A at 5 V and 10 A at 12 V outputs. The         process is then repeated by the 3DR Pixhawk flight controller 5         sending a signal to turn off the blower and index the rotary         cartridge holder to the next position.

The goal for the sampler design was to have a high flow rate while maintaining a high static pressure to be able to move the air across the sampling cartridge. Applicant recognized that the main limiting factor to the design was weight followed by power consumption. Weight is the main limiting factor because the sUAS, as described above, uses roughly 120 watts/kg to hover even if the blower is not operating. Developing a light weight sampler was therefore crucial in order to have a sUAS that could have a long endurance and be able to lift the payload.

The power consumption needed to be limited because the lightweight electronics needed to run the centrifugal blower become extremely limited above 10 A for off the shelf components. Also, all sUAS applications must consider the current required by the blower in order to keep the current within the specified current that the battery can discharge safely, and within the voltage regulator specifications, if applicable. The current the battery can safely discharge is in turn dependent on the battery specification (make, cells, voltage, type, etc.).

The target time per air sample was roughly 1 minute which would require a volume of 150 liters to flow through the sample cartridge [mTrap, Assured Bio Labs, 228 Midway Lane, Suite B, Oak Ridge, Tenn.].

Fan and Blower Considerations

The baseline samplers in the mold industry are piston-type positive displacement compressors. Two examples of the baseline pump are: 1) Environmental Monitoring Systems' MegaLite IAQ Pump, which has a flow rate of 30 liters per minute (LPM) with a mass of 2.5 kg and is powered at 115 V and 0.46 A; and 2) Zefon's Z-Lite IAQ Air Sampling Pump, which has a flow rate of 30 LPM with a weight of 3.6 kg. When a technician is sampling with these types of pumps they take roughly 5 minutes to collect a sample when sampling at 30 LPM, assuming a sample of 150 liters is needed for the mTrap cartridge. The heavy weight of 2.5-3.6 kg for these two examples would significantly reduce the sUAS flight time for the air frame and power supplies described in the previous example. The low throughput of these two candidates ruled out the industry standard for sUAS applications since the sUAS has a flight time of roughly 32 minutes down to 20% battery remaining. The low throughput would not allow enough samples to be taken per flight for sampling to be cost effective over large areas.

Based on the fact that positive displacement pumps were deemed to adversely limit performance, Applicant undertook research into axial fan designs because of their high flow rate and relatively low power consumption. Applicant quickly discovered that such axial fans are considered generally unsuitable for use as a vacuum pump. What this means is that fans are traditionally designed to operate with the inlet open to the atmosphere, i.e., with no restriction or pressure drop at the inlet side, and to provide flowing air at the outlet side. Applicant, by contrast, sought to place the sampling cartridge, i.e., the flow restriction, on the inlet side of the fan and thereby utilize a blower as a suction pump and not as it was intended to be used. The sampling cartridge needed to be placed on the inlet side of the pump to reduce the risk of preexisting contaminants inside the pump housing from contaminating the sample, which would give a false reading.

FIGS. 7-17 illustrate various configurations of fans in order to make the discussions that follow more clear.

Example

-   -   The first attempt to adapt an axial fan, FIG. 7, to this problem         used a fan [Corsair SP120 High Performance Edition, 47100         Bayside Parkway Fremont, Calif.], which had an airflow of 62.74         cubic feet per minute (CFM), Static Pressure of 3.1 mm H₂O, and         a Power Draw of 0.18 A at 12 V. When the Corsair axial fan was         fitted to the sample cartridge, it yielded no measurable air         flow through the sample cartridge, because the static pressure         wasn't high enough to overcome the resistance caused by the         sample cartridge. With such a low airflow from such a relatively         high performance axial fan, the axial fan design was rejected.         The Corsair SP120 High Performance fan had a mass of 0.2         kilograms.

Applicant postulated that a centrifugal blower in backward facing blades, FIG. 9, might be better suited for sUAS applications because of their increased efficiency over radial (FIG. 11) or forward (FIG. 10) facing blades. Backward facing blades also produce a high flow rate at a high pressure and will not overload with changes in static pressure, possibly allowing for a variety of sampling cartridges to be used, with varying flow restrictions, with a single blower design.

Example

-   -   The first centrifugal blower with backward facing blade to be         selected for trial was the Model BFB04512HD [Delta Electronics,         252 Shang Ying Road, Kuei San Industrial Zone, Taoyuan Shien,         Taiwan], which is a backward facing blade design that does not         have a shroud connected to the blades. According to the         manufacturer's specifications it is capable of flowing 138.8         liters per minute (LPM) and a static pressure of 9.3 mm H₂O. The         power consumption is 12V at 0.1 A.

Applicant inquired with the manufacturer for information on the performance of the aforementioned blower when configured to be run as a suction device (i.e., with a restriction on the intake side and the outlet free to ambient air) and was advised by the manufacturer that “our blowers cannot be run as a vacuum.”

Example

-   -   Despite the manufacturer's recommendation to the contrary,         Applicant fitted the BFB0512HD blower to the sample cartridge,         and discovered, surprisingly, that it achieved a flow rate of         1.3 LPM. This was a drastic improvement over the Corsair axial         flow fan, providing a larger flow rate with a lower power         consumption.

Based on this discovery that a blower could be adapted to the sampling problem, Applicant began testing different blower designs and configurations.

Example

-   -   To maximize the efficiency of the centrifugal blower, the         backward facing blades were equipped with a completely enclosed         shroud 121 attached to the blades on one side and open on the         other as shown generally in FIG. 12. Having the fully-closed         shroud attached to the blades on only one side not only improves         efficiency but also allows for easy cleaning of the blades if         the blower becomes contaminated since one side is open. A         centrifugal blower that met this description was the Intex         Quick-Fill 080 pump that is powered at 12 V at 8 A and normally         intended to be used to blow air into inflatable mattresses and         the like, with its inlet side open to ambient pressure. The         factory specification for this pump is 600 LPM and a static         pressure of 323.41 mm H₂O. When tested in the lab with the mTrap         sample cartridge in place the Intex pump produced a flow rate of         at least 50 LPM. The blower had a mass of 1.2 kg.

Example

-   -   Several additional features of the blower 11 are shown         schematically in FIGS. 12-17. The drive shaft 83, 83′, 83″ is         held in a hub 81, 81′, 81″, and may extend on either or both         sides of the fan itself. In the example shown in FIG. 12, shaft         83 is driven directly by a motor contained within an integral         housing, but it will be appreciated that the shaft might be         belt-driven if that design might allow more convenient placement         of various components on a particular airframe. Blower case may         be provided with a hole on the back side as shown in FIGS. 15         and 17 to accommodate the shaft and hub if the drive is placed         on the back side.

Example

-   -   One application for the invention is for sampling airborne mold.         For this task, the sampler was configured to use a cartridge as         generally described in U.S. Pat. No. 9,170,178. One suitable         cartridge is Assured Bio Labs mTrap. The mTrap works by         capturing pathogens or particulates by blowing the atmosphere         across a filter.

It will be appreciated that many other air sampling problems exist, for which the invention may be adapted by using other kinds of sample cartridges. For example, a cartridge containing gold or copper wool could be used to collect airborne mercury vapor for monitoring emissions from mines, power plant stacks, and other potential sources of elemental Hg emissions. Activated carbon could be used to capture radon or various chemicals, particularly organics. Air sampling around cooling towers could be used to detect not only mold but also very fine water droplets for analysis to detect Legionella or other pathogenic microbes. Furthermore, filtration per se, is not the only means to capture a sample; inertial impaction or deposition onto a tacky or adhesive surface may also be used, as, for example, in the Air-O-Cell® sampling cassette (Zefon International, Inc., 5350 SW 1st Lane, Ocala, Fla. 34474). Other means of sample collection can include sedimentation, impingement, impaction, slit-to-agar impactors, sieve impactors, centrefugil impactors, and membrane filtration. The skilled artisan may adapt the invention to such applications and variants using routine experimentation.

As noted previously, a typical mission is contemplated to consist of maneuvering the sUAS into position at selected places that define a sampling pattern, keeping the sUAS in each place while drawing a predetermined amount of air through one sample cartridge, then indexing to another cartridge and moving to another place, and so on until the entire supply of cartridges has been filled with samples, then returning to base so that the cartridges can be removed for analysis. The steps of the method are shown schematically in FIG. 18. It will be appreciated that steps 1004-1006 will be repeated for each sample collected during the mission.

Example

-   -   One suitable method for accommodating multiple samples is a         circular carousel, as shown generally in FIGS. 1-3, that is         indexed by rotation from one index position to the next as         indicated by the curved arrow in FIG. 2. The circular carousel         method eliminates the change in center of gravity (CG), allowing         for constant flight characteristics and keeps the CG within the         aircraft specifications. It will be appreciated, however, that         other means exist to achieve the same purpose.     -   A square or rectangular array plate may be constructed to hold         the cartridges. The plate would be slidably mounted so that X-Y         actuators or steppers may index sequentially from one sample to         the next.     -   The cartridges may be mounted in a single row in a magazine 41         similar to an ammunition magazine as shown schematically in         FIG. 4. An actuator 44-45 may be placed at one end of the         magazine and each cartridge 10 may be advanced in turn, with a         spring 42 in the other end (dead space) of the magazine to work         against the actuator and keep the cartridges in place. Openings         on the top and bottom of the magazine would allow the air to         flow through the particular cartridge that is under inlet 8 of         the blower.     -   The cartridges may be mounted in two spirals in a magazine 41′         similar to a dual-drum ammunition magazine as shown         schematically in FIGS. 5-6. The driving spiral drum would have a         servo 64 connected to a telescoping arm 63. The telescoping arm         would rotate the cartridge plate 62, tracking along the spiral.         As the telescoping arm rotated, it would index the cartridge 10         into position. The expended cartridges would then be indexed         into the unloading drum while compression is applied to the         cartridges via unloading spring 65, unloading telescoping arm         61, and unloading cartridge plate 66. It is noted that existing         ammunition drum magazine design principle could be adapted for         the use of sample cartridges. One such device is the familiar         Soviet-era PPSh-41 drum magazine.

Example

-   -   The sUAS can be controlled manually by a ground station or         handheld radio transmitter 15 or programmed before launch so         that the entire mission can be conducted autonomously.     -   The ground station consists of two parts that can be run         simultaneously or independently, the handheld transmitter and/or         application running on a laptop or other device. The handheld         ground control requires full manual control of the sUAS to         conduct a flight and requires the operator to have existing sUAS         experience. Using the handheld ground control however does not         require the use of GPS since the aircraft is being flown         visually within line of sight.     -   The application on a laptop or other device does not require any         sUAS experience, it does however require the use of a GPS. The         pilot operates the sUAS from the laptop by clicking on commands         in the application and clicking on locations on a downloaded map         to fly to a given waypoint at a given altitude. Both the         handheld and laptop parts of the ground station send telemetry         on independent radio frequencies, some of the information         includes battery voltage, power consumed, altitude, ground speed         and distance from home location.     -   The sUAS can fly fully autonomously without the use of a ground         station after it is launched, even though contact with a ground         station is recommended, by uploading data to the flight         controller before launch. The flight plan is created in the         application by setting a home location, waypoints, actions at         waypoints, takeoff actions, and landing actions. The flight plan         data is then transferred to the sUAS via a USB cable or a radio         modem and stored on the flight controller memory.

It will be understood that Applicant's use of the term “autonomously” simply implies that the sUAS is navigating from place to place without the real-time intervention of a ground controller. The skilled artisan will be aware that terminology in the field may vary, e.g., some authors distinguish between “semi-autonomous navigation”, which they regard as somewhat blindly following a preprogrammed path, versus “fully autonomous navigation” in which the vehicle has the ability to observe and adapt to its environment, for instance recognizing and maneuvering around obstacles that are encountered unexpectedly. Any of these operational variants are considered to be within the scope of the present invention.

Example

-   -   Comparing the air flow diagram, FIG. 19 to the mechanical         diagram, FIG. 3, shows how the invention uses the blower to         achieve two completely separate operations, viz., drawing air         through the sample cartridge via intake pipe 8 and providing         forced cooling for some of the on board electronics via exhaust         structure 32. Having the regulator 31 placed in the exhaust         airflow from the blower 11 allows for the regulator to run         cooler which in turn increases the reliability. The cooling from         the exhaust is especially important when the Intex Quick-Fill         080 blower is operating constantly and not being run         intermittently (longer than 2 minutes).     -   In addition to keeping the regulator cool, this design further         allows the user to keep the voltage regulator on the blower         attachment, which reduces the need to keep an extra voltage         regulator on the sUAS when the blower assembly is not attached.         Having the voltage regulator on the blower attachment keeps all         the necessary systems onboard, allowing for blower attachments         to be moved between different sUAS.     -   It should be noted that the blower 11 could run directly from         the battery. This would eliminate the need for a voltage         regulator, but only provided that the motor is rated for the         battery's output.

Example

-   -   Each sampling cartridge 10 is preferably fixed with a unique         identifier (typically a serial number, barcode, or RFID tag).         When the sampling cartridge is loaded onto the sampling revolver         the pilot logs the cartridge's specific position in the rotary         cartridge holder 14. Once the drone is airborne and collecting         the geographical location through the GPS or other geolocation         means, a sample is taken by activating the blower. The unique         identifier is then used to reference which sample was collected         at the given geographical location. The sample is then sent to         the lab for analysis and the information that is recorded is         entered into a database which correlates the geolocation and lab         information.

Example

-   -   Future designs using a magazine style cartridge would reduce the         amount of potential error from manually recording the position         of the sampling cartridge on the revolver and the possibility of         indexing the incorrect cartridge on the revolver. The magazine         design also reduces the amount of samples that need to have a         unique identifier since only an identifier would be needed on         the magazine 41 or 41′ to identify it with a particular mission.         In other words, the testing lab could supply the entire loaded         cartridge or carousel as a single unit, and the user would         return the entire unit to the testing lab, where it would be         automatically unloaded, tested, and reloaded with new         cartridges. The magazine design also reduces the chance of cross         contamination from ground contaminants being disturbed from the         rotor wash or while the operator is installing/removing the         sampling cartridges.

It will be appreciated that magazines may exploit spring tension to perform the physical work of moving from one cartridge to the next. Such an approach has the further benefit of potentially reducing system mass and power requirements, because motors might be eliminated and battery draw can be reduced, as the spring can be preloaded before the flight begins and the stored mechanical energy replaces energy that otherwise would have been supplied by the battery.

Example

-   -   It will be appreciated that when a sUAS is operating completely         autonomously, following a preprogrammed flight plan, there is         the danger that obstacles may exist that create the hazard of         collision. The invention may therefore be further modified to         incorporate any suitable on-board collision avoidance system,         such as those based on scanning lidar, radar, visual or         ultrasonic ranging, etc., as are known in the art.

Example

-   -   The preceding examples in many cases contemplate that the         sampling uses one or more sampling cartridges 10, which are         generally contemplated to be single-use, disposable, or         partially disposable. That is to say, when a cartridge is sent         for analysis, the testing laboratory might discard the used         cartridge; alternatively, it might disassemble the cartridge,         remove the test article (e.g., the filter medium), and perhaps         reassemble the cartridge with a new test article in a re-used         housing. Thus, the amount of any cartridge that is configured or         intended to be re-used may vary depending on the particular         trade-offs of economics, labor, and contamination or cleaning         issues that might be involved.

Example

The Invention may also be configured to perform analyses in real time or near real time, by replacing the sample cartridge(s) with a test cell that can perform some physical test in the flowing air without the need to capture a sample for analysis off-line. Applicant contemplates many uses for this variant. For example, sensitive gas sensors are well known in the art, which are optimized for particular gases or vapors (e.g., ethanol, hydrogen, CO, combustible gases, etc.). Thus, the cartridge may be replaced with a flow cell in which a combustible gas sensor is operating, and the sUAS could then be used to survey an area for hazardous gas leaks (e.g., the site of a railroad accident involving tankers of volatile substances. In another contemplated application, the flow cell may include an optical scattering detector that would quantify the level of smoke, dust, water vapor, or other items of interest for applications in meteorology, environmental monitoring, regulatory compliance, and the like.

As described in the examples, an essential feature of the invention is the collection of samples at a plurality of well-defined geolocations. Although for convenience, some of the foregoing examples refer to GPS as a shorthand for geolocation information, it will be understood that the standard Global Positioning System is only one of several geolocation protocols. Furthermore, if the sUAS is operating inside of a building or enclosed space, it might be more accurate and convenient to deploy an ultrasonic triangulation system within the working space. Any suitable means for determining the location of each sample within a suitable geospatial coordinate system at an acceptable level of accuracy may be used, and all such means are considered to be within the scope of the invention.

As described in several of the examples, Applicant contemplates that the sUAS will, in general, move from place to place and then remain or loiter at selected locations for a sufficient time to collect a valid sample. The sUAS may loiter by hovering in place while the sample is collected; alternatively, the vehicle might land and collect a sample while completely stationary (e.g., at selected places on the roof of a building near air conditioning towers, etc.) For the case in which real-time or near real-time sampling is done, as in the case of continuously monitoring the atmosphere as it flows through a tube, then the loitering time may be very short in that the sUAS might be continuously moving at a low speed. In such cases, the time stamp would be associated with a geolocation that includes a volume of space defined by the speed of the vehicle and the time to collect a measurement.

IDENTIFICATION OF COMPONENTS BY REFERENCE NUMERAL

-   -   Item Description     -   1 Propeller     -   2 Motor     -   3 Frame Arm     -   4 Navigation and Radio     -   6 Controller     -   6 Power     -   7 Payload Support     -   8 Intake Pipe     -   9 Connecting Pipe     -   10 Sample Cartridge     -   11 Blower Case     -   12 Servo     -   13 Base Plate     -   14 Rotary Cartridge Holder     -   15 Ground Control     -   31 Voltage Regulator     -   32 Voltage Regulator Attached to Blower Exhaust     -   41 Magazine     -   41′ Drum Magazine     -   42 Spring     -   43 Spring Plate     -   44 Actuator Plate     -   45 Actuator     -   61 Unloading Cartridge Telescoping Arm     -   62 Loading Cartridgo Plate     -   63 Telescoping Loading Arm     -   64 Servo Motor Hub     -   65 Spring Hub     -   66 Unloading Carriage Plate     -   71 Blower Exhaust     -   72 Blower Intake     -   81 Blower Hub     -   82 Backward Facing Blade     -   82′ Forward Facing Blade     -   82″ Axial Blade     -   121 Shroud Attached to Blade 

I claim:
 1. An atmosphere sampling system comprising: an unmanned rotary-wing aircraft platform comprising: an airframe capable of lifting a selected payload mass; at least one motorized rotor; and, a flight control system including an on-board controller; an atmosphere sampling unit having a total mass no greater than said selected payload mass, and comprising: a centrifugal blower having blades of a selected orientation, an inlet structure to draw in an atmosphere to be sampled, and an outlet to discharge said atmosphere after sampling; a plurality of sample containers, each having a sample collecting medium therein; and, an indexing mechanism to move selected sample containers, one at a time, into contact with said inlet structure so that samples may be collected on said sample collecting medium; and, a power supply with sufficient capacity to operate said at least one motorized rotor, said onboard controller, said centrifugal blower, and said indexing mechanism.
 2. The system of claim 1 wherein said flight control system includes said on-board controller in radio communication with a ground-based control station.
 3. The system of claim 1 wherein said flight control system is preprogrammed to autonomously follow a selected route and a selected sample collection schedule.
 4. The system of claim 1 wherein said flight control system records geolocation data associated with each sample, so that each sample may be identified with a specific collection location.
 5. The system of claim 1 wherein said power supply includes a voltage regulator.
 6. The system of claim 5 wherein said voltage regulator is positioned proximate to the outlet of said blower so that air flow from said blower will remove heat from said voltage regulator.
 7. The system of claim 1 wherein said sample containers are held in a generally circular carousel that is rotatable by said indexing mechanism in order to bring a selected sample container into position for sample collection.
 8. The system of claim 1 wherein said sample containers are held in a plate that is movable by said indexing mechanism in two orthogonal directions to bring a selected sample container into position for sample collection.
 9. The system of claim 1 wherein said sample containers are loaded single-file in a magazine and are moved in a stepwise manner within said magazine by said indexing mechanism in order to bring a selected sample container into position for sample collection.
 10. The system of claim 1 further including at least one sensor selected from the group consisting of: chemical sensors, combustible gas sensors, CO sensors, hydrogen sensors, thermal sensors, hydrogen sulfide sensors, optical sensors, video cameras, microphones, IR detectors, UV detectors, optical particulate detectors, and radiation sensors.
 11. The system of claim 1 wherein said centrifugal blower comprises backward-facing blades. 